JP2006207772A - Transmission belt and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission belt and a manufacturing method thereof, favorably maintaining the arrangement of core wires to prevent the generation of a void between the core wires and inhibit dynamic separation of core wires, having durability, and lowering the cost. <P>SOLUTION: In this transmission belt 1, an adhesive rubber layer 3 is disposed to enclose the core wire 2 formed of cords along the longitudinal direction of the belt, a rib rubber layer 4 is provided to closely adhere to the adhesive rubber layer 3, and canvas is not stacked on the back 5 and the inside part to expose the respective rubber layers 3, 4. Since the adhesive rubber layer 3 is provided to completely enclose the periphery of the core wires 2, turbulence of the core wires 2 is not caused in pressing in a rubber composition, and also compressive deformation of the core wires 3 is avoided to prevent the generation of a void, so that stable running of the belt is secured, and separation in the interface between the core wires and the adhesive rube is not caused. The component members are decreased in number to provide the transmission belt at a low cost. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power transmission belt and a method for manufacturing the power transmission belt, and more particularly, to maintain a favorable arrangement of the core wires, prevent dynamic peeling of the core wires, and have excellent durability and a low cost. About.

  Various methods are used for molding rubber, elastomers, and resin materials into some shape, but in methods other than compression molding, that is, transfer molding, press molding, injection molding, etc., the material and mold are It is well known that large shearing force and frictional force are generated between them. These forces are particularly prominent when molding thin materials. For example, when manufacturing a flat belt or a toothed belt such as a transfer belt, a cylindrical vulcanization mold is used, and a cylindrical mold is installed on the outer periphery of the vulcanization mold. The thermoplastic rubber composition was pressed into the cavity.

  For example, in the formation of a toothed belt, transfer molding is also disclosed in which a thermoplastic rubber composition is pressed into a cavity of a mold. (Patent Document 1)

When V-ribbed belts are formed by transfer molding or press-fitting, a cord core is wound around the surface of the core mold in a spiral, and then inserted into an outer mold with rib grooves, and is thermoplasticized in the rubber reservoir. After containing the rubber compound, the upper mold equipped with the press-fit piston was pressed to fill the cavity while allowing the pressurized rubber compound to flow. Thereafter, the outer mold was heated and vulcanized. After vulcanization, the upper mold was raised, the core mold was removed, and the belt sleeve was removed from the outer mold.
JP 2003-334865 A

  However, in the case of conventional transfer molding or press-fitting molding, it is difficult to remove the core mold. In particular, when forming a V-ribbed belt, the belt sleeve is in close contact with the outer mold with rib grooves, so that the interface between the belt sleeve back surface and the core mold was slid when the core mold was removed. When the core mold has a large pull-out force and does not come out smoothly, the belt sleeve may be damaged due to stress concentration.

  Furthermore, during molding, the press-fitted rubber composition sometimes disturbs the arrangement of the core wires due to a large shearing force. When the obtained belt is run, it may be easy to meander, and a so-called pop-out phenomenon may occur in which the core wire peels off early. In addition, the core wire was compressed and deformed when the rubber composition was press-fitted to form a space between the core wires, and the rubber compound could not be sufficiently filled between the core wires and remained as a void. As a result, the molded belt is affected by voids, causing a pop-out phenomenon due to dynamic peeling, and cracks may occur at an early stage.

  The present invention has been made in view of the above points, and maintains the arrangement of the cores well, prevents the occurrence of voids between the cores and prevents the dynamic separation of the cores, and is excellent in durability. Another object of the present invention is to provide a low-cost transmission belt and a manufacturing method thereof.

In the first and second aspects of the present invention, an adhesive rubber layer surrounding the cord made of the cord is disposed along the belt longitudinal direction, a rib rubber layer is provided in close contact with the adhesive rubber layer, and the belt back surface and the abdominal surface are provided. Is a transmission belt in which each rubber layer is exposed without laminating the canvas, and since the adhesive rubber layer completely surrounds the core wire, the core wire is not disturbed when the rubber composition is pressed. In addition, since the compression deformation of the core wire is avoided and no void is generated, stable belt running is ensured, and there is no peeling when the belt runs at the interface between the core wire and the adhesive rubber, and the durability is excellent. Since components such as canvas are not used, a low-cost transmission belt is obtained.
Moreover, a short fiber can also be contained in a compression rubber layer, and the side pressure resistance of a compression rubber layer improves.

  In the invention of claim 3 of the present application, at least one rib in which a core wire made of a cord surrounded by an adhesive rubber is spun on the surface of the resin mold and the core mold on which the resin mold is mounted is engraved along the inner peripheral surface. A cavity for forming a rib rubber layer is provided by fitting into an outer mold having a groove, and the kneaded and fluidized rubber composition is once pooled in a rubber reservoir, and then the rubber composition is pressed into the cavity to form a rib rubber layer. The power transmission belt manufacturing method includes forming a belt sleeve by molding, vulcanizing, and removing the core mold at the interface between the belt sleeve and the resin mold. In the present invention, the core wire surrounded by the adhesive rubber is spun on the surface of the resin mold to eliminate the gap between the adhesive rubbers, and then the rib rubber layer is formed. There is no disturbance, there is no compression deformation of the core wire, and no voids occur. Moreover, since the core mold is removed at the interface between the belt sleeve and the resin mold, the mold removal operation is facilitated.

  In the inventions according to claims 4 to 8 of the present application, in order to easily hold the resin mold to the core mold, when the outer surface of the core mold is knurled, the resin mold is a polyether ether ketone resin, a polyimide resin, If the core is made of at least one selected from polytetrafluoroethylene resin, polymethylpentene resin, and ultrahigh molecular weight polyethylene resin, or a cord composed of a pair of S-twisted and Z-twisted cords surrounded by adhesive rubber Or when the cross section of the core wire surrounding the adhesive rubber is rectangular or flat, or in the cross section of the core wire surrounding the adhesive rubber, the area occupied by the adhesive rubber is 20 to 150%, This includes the case where an ethylene-α-olefin elastomer that is easily plasticized by being thermoplasticized as a rubber composition is used for the main rubber.

  In the transmission belt of the present invention and the manufacturing method thereof, since the adhesive rubber layer exists so as to completely surround the core wire, there is no disorder of the core wires during the press-fitting of the rubber composition. Since no compression deformation occurs and no voids are generated, there is no peeling when the belt runs at the interface between the core wire and adhesive rubber, making it a highly durable transmission belt. There is an effect that the demolding work becomes easy because the mold is demolded at the interface.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
1 is a cross-sectional perspective view of a transmission belt according to the present invention, FIG. 2 is a cross-sectional view of a device for adhering adhesive rubber to a core wire, FIG. 3 is a cross-sectional view of the core wire used, and FIG. FIG. 5 is a schematic view, and FIG. 5 is an enlarged view of part A of FIG.

  As shown in FIG. 1, the transmission belt 1 of the present invention is provided with an adhesive rubber layer 3 so as to surround a core wire 2 composed of an S-twisted cord 2a and a Z-twisted cord 2b along the belt longitudinal direction. A plurality of rib rubber layers 4 having a substantially triangular cross section extending in the belt longitudinal direction in close contact with the layer 3 are provided, and no canvas is laminated on the belt back surface 5 and the abdomen surface 6. 4 has a belt structure with few constituent members exposed.

  As the core 2, polyester fiber, aramid fiber, and glass fiber are used. Among them, the total number of deniers obtained by twisting together polyester fiber filaments having ethylene-2,6-naphthalate as a main constituent unit is 4,000 to 8, A cord subjected to adhesion treatment of 000 is preferable in order to reduce the belt slip ratio and extend the belt life. The number of upper twists of this cord is 10 to 23/10 cm, and the number of lower twists is 17 to 38/10 cm. When the total denier is less than 4,000, the modulus and strength of the cord are too low. When the total denier is more than 8,000, the belt becomes thick and the bending fatigue property is deteriorated.

  Examples of the adhesive rubber layer 3 include natural rubber, butyl rubber, styrene-butadiene rubber, chloroprene rubber, ethylene-propylene rubber, alkylated chlorosulfanated polyethylene, hydrogenated nitrile rubber, hydrogenated nitrile rubber, and unsaturated carboxylic acid metal salt. Or a rubber material such as ethylene-α-olefin elastomer made of ethylene-propylene rubber (EPR) or ethylene-propylene-diene monomer (EPDM), or a mixture thereof. As examples of the diene monomer, dicyclopentadiene, methylene norbornene, ethylidene norbornene, 1,4-hexadiene, cyclooctadiene, and the like can be used. Furthermore, a softener, a reinforcing agent composed of carbon black, a filler, an antiaging agent, a vulcanization accelerator, a vulcanizing agent, and the like are added to the rubber.

  Examples of the softening agent include general rubber plasticizers, such as phthalates such as dibutyl phthalate (DBP) and dioctyl phthalate (DOP), adipates such as dioctyl adipate (DOA), and dioctyl sebacate (DOS). Sebacates, phosphates such as tricresyl phosphate, etc., or general petroleum softeners are included.

  In the cross section of the core wire 2 having the adhesive rubber layer 3, the area occupied by the adhesive rubber layer 3 is 50 to 80%.

  The rubber used for the rib rubber layer 4 is the same as that of the adhesive rubber layer 3, and preferably an ethylene-α-olefin elastomer made of ethylene-propylene-diene monomer (EPDM) that is easily thermoplasticized and press-fitted. . Examples of diene monomers include dicyclopentadiene, methylene norbornene, ethylidene norbornene, 1,4-hexadiene, cyclooctadiene, and the like.

  The rib rubber layer 4 is made of fibers such as aramid fibers, polyamide fibers, polyester fibers, and cotton, and the length of the fibers varies depending on the type of fibers, but short fibers of about 1 to 10 mm are used. For example, the aramid fibers are About 3 to 5 mm, polyamide fibers, polyester fibers, and cotton are about 5 to 10 mm. The amount of addition is 10 to 40 parts by weight with respect to 100 parts by weight of rubber. Furthermore, a softener, a reinforcing agent composed of carbon black, a filler, an antiaging agent, a vulcanization accelerator, a vulcanizing agent, and the like are added to the rubber of the present invention.

  In the rubber composition used for the rib rubber layer 4, a silicone-acrylic resin copolymer powder can also be used. In this case, 5 to 20 parts by mass, more preferably 5 to 15 parts by mass of the silicone-acrylic resin copolymer powder is mixed with 100 parts by mass of the raw rubber, and a reinforcing agent such as carbon black or silica, or an antioxidant is added thereto. A vulcanization accelerator, a vulcanizing agent composed of sulfur or peroxide, and a co-vulcanizing agent are added.

  When the addition amount of the silicone-acrylic resin copolymer is less than 5 parts by mass, a decrease in the friction coefficient with the pulley surface cannot be expected, and when it exceeds 20 parts by mass, the modulus is 100% modulus and the elongation at cutting is increased. The rubber physical properties such as the above are lowered, and the belt durability is also lowered.

  The silicone-acrylic resin copolymer powder is a powder having an average particle size of 30 to 250 μm, which has an excellent surface sliding effect of the silicone resin and compatibility with the polymer in the acrylic part. Charine R manufactured by Nissin Chemical Industry is known.

  For crosslinking between the rubber composition and the adhesive rubber, sulfur or organic peroxide is used. Specific examples of the organic peroxide include di-t-butyl peroxide, dicumyl peroxide, t-butylcumyl peroxide, 1.1-t-butylperoxy-3.3.5-trimethylcyclohexane, and 2. 5-di-methyl-2.5-di (t-butylperoxy) hexane, 2.5-di-methyl-2.5-di (t-butylperoxy) hexane-3, bis (t-butylperoxydi-isopropyl) benzene, Examples include 2.5-di-methyl-2.5-di (benzoylperoxy) hexane, t-butylperoxybenzoate, and t-butylperoxy-2-ethyl-hexyl carbonate. This organic peroxide is usually used alone or as a mixture in the range of 0.005 to 0.02 mol g per 100 g of rubber.

  Moreover, you may mix | blend a vulcanization accelerator. Examples of vulcanization accelerators include thiazole, thiuram, and sulfenamide vulcanization accelerators. Specific examples of thiazole vulcanization accelerators include 2-mercaptobenzothiazole, 2-mercaptothiazoline, dibendiazyl, Disulfide, zinc salt of 2-mercaptobenzothiazole, and the like, and thiuram vulcanization accelerators include tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, N, N′-dimethyl. -N, N'-diphenylthiuram disulfide and the like, and as the sulfenamide vulcanization accelerator, specifically, N-cyclohexyl-2-benzothiazylsulfenamide, N, N'-cyclohexyl-2 -Benzothiazylsulfenamide and the like. As other vulcanization accelerators, bismaleimide, ethylenethiourea, and the like can be used. These vulcanization accelerators may be used alone or in combination of two or more.

  Further, by adding a co-agent, it is possible to increase the degree of cross-linking and prevent problems such as adhesive wear. Examples of the crosslinking aid include TIAC, TAC, 1,2 polybutadiene, metal salt of unsaturated carboxylic acid, oximes, guanidine, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, NN′-m- Usually used for peroxide crosslinking such as phenylene bismaleimide and sulfur.

  When the adhesive rubber layer 3 is continuously surrounded and attached to the surface of the cord 2 made of the cords 2a and 2b, as shown in FIG. 2, the cord 2 is guided to the guide hole 10 of the guide member 13 attached to the die 12a. It is inserted and traversed through the main passage 11, and is extracted from the through passage 14 and the opening portion 15 so that it can run.

  Subsequently, after adjusting the die temperature to 60 to 120 ° C., the rubber 17 kneaded and extruded by the extrusion screw 16 is provided on the outer periphery of the die 12b. The bypass passage 19, the linear main passage 11, and the discharge passage 20 are provided. The fluid is discharged without stagnation. The rubber 17 splits the bypass passage 19 into a 180 ° clockwise route and a counterclockwise route, merges again, and is discharged from the discharge passage 20 to the outside. At the same time, the rubber 17 is discharged from the discharge passage 20 to the outside through the main passage 11. The At this time, the valve of the discharge passage 20 is fully opened to increase the amount of rubber discharged.

  When the internal pressure of the main passage 11 is increased with the valve of the discharge passage 20 slightly tightened, rubber adheres while the cord 2 runs at 5 to 10 m / second, and the rubber adheres through the through passage 14 of the rubber-covered mold 21. Is fixed to the surface of the cord, and the cord coated with rubber is cooled and dried to make the core of the transmission belt.

  When the rubber coating is stopped, the cord is not pulled out, and the passage of the discharge passage 20 is fully opened until there is no rubber charged in the extruder, so that the amount of rubber discharged is increased to improve the rubber flow. The discharged rubber can be reused.

  As shown in FIG. 3, the cord 2 processed in this way completely surrounds the S-twisted cord and the Z-twisted cord 2a, 2b with the adhesive rubber layer 3, and the cross-sectional shape is also square or rectangular. It may be rectangular or flat. However, the rectangular shape is preferable for arranging the cores 2 without gaps. Of course, one cord surrounded by the adhesive rubber layer 3 can also be used. However, if the cord 2 in which the two cords are covered with the adhesive rubber layer 3 is used, the twisted wrinkle of the cord is eliminated, so that spinning is performed. Can be eliminated, and the spinning time can be shortened. When the Z twist and the S twist are used in pairs, the vibration of the molded belt and the occurrence of vibration are reduced.

  A core wire 2 composed of a pair of cords 2a and 2b of S twist and Z twist surrounded by the adhesive rubber layer 3 is wound around the surface of a resin mold 31 attached to the core mold 30 by a spinning device, and adjacent adhesive rubber layers Close the three. The surface of the core mold 30 may be knurled to improve the tie with the resin mold 31.

  The resin mold 31 used here is at least one selected from polyether ether ketone resin, polyimide resin, polytetrafluoroethylene resin, polymethylpentene resin, and ultrahigh molecular weight polyethylene resin, and has excellent sliding characteristics. It is a resin layer having a thickness of 0.2 to 5.0 mm. The resin mold 31 can be mixed with a reinforcing material such as glass fiber and a lubricant such as molybdenum disulfide.

  The core mold 30 is fitted into an outer mold 33 previously installed on the base table 32, and a cavity 35 for forming a rib rubber layer is formed in the gap between the core mold 30 and the outer mold 33. The outer mold 33 has a plurality of rib grooves 36 engraved along the inner peripheral surface.

  The rubber composition to be used is kneaded and thermoplasticized by the injection molding machine 37, and is pooled by an amount substantially equal to the volume of the cavity 35 in the rubber reservoir 38 provided along the outer periphery of the core mold 30. A rubber composition 42 fluidized by pressurizing the inside of the rubber reservoir 38 with a predetermined pressure by the piston 41 of the compressor 39 is press-fitted into the cavity 35. The filled rubber composition 42 is heated and vulcanized at 120 to 160 ° C. for 20 to 30 minutes.

  When the vulcanization is completed, the injection molding machine 37, the compressor 39 and the piston 40 are moved backward, the core mold 30 is moved to another place and pressed at a predetermined pressure, and at the interface between the belt sleeve 43 and the resin mold 31. Slide to demold. Then, the belt sleeve 43 attached to the outer mold 33 is taken out and the molding is finished.

  The manufacturing method of the transmission belt of the present embodiment is as described above, but a release agent such as silicone oil can be applied to the surface of the resin mold 31 to improve the slip. Alternatively, the resin mold 31 can be fitted into the core mold 30 after only the resin mold 31 is installed in the spinning device and the core wire 2 is wound.

It is a section perspective view of the power transmission belt concerning the present invention. It is the schematic of the apparatus which adheres adhesive rubber to a core wire. It is sectional drawing of the core wire to be used. It is the schematic of the manufacturing apparatus of a transmission belt. It is the A section enlarged view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transmission belt 2a S twisted cord 2b Z twisted cord 2 Core wire 3 Adhesive rubber layer 4 Rib rubber layer 5 Belt back surface 6 Belt belly surface 30 Core type 31 Resin type 33 Outer type 35 Cavity 36 Rib groove

Claims (9)

  An adhesive rubber layer that surrounds the cord made of cords is disposed along the belt longitudinal direction, a rib rubber layer is provided in close contact with the adhesive rubber layer, and each rubber layer is formed without laminating canvas on the back and abdominal surfaces of the belt. A transmission belt characterized by exposure.   The power transmission belt according to claim 1, wherein the compressed rubber layer contains short fibers. Spinning the cord made of cord surrounded by adhesive rubber to the surface of the resin mold,
A cavity for forming a rib rubber layer by fitting the core mold with the resin mold into an outer mold having at least one rib groove engraved along the inner peripheral surface;
After the kneaded and fluidized rubber composition is once pooled in the rubber reservoir, the rubber composition is pressed into the cavity to form a rib rubber layer,
Vulcanized to make a belt sleeve,
Demolding the core mold at the interface between the belt sleeve and the resin mold,
A manufacturing method of a transmission belt characterized by the above.   The method for manufacturing a transmission belt according to claim 3, wherein the outer surface of the core mold is knurled.   The method for producing a transmission belt according to claim 3, wherein the resin mold is at least one selected from polyether ether ketone resin, polyimide resin, polytetrafluoroethylene resin, polymethylpentene resin, and ultrahigh molecular weight polyethylene resin.   The method for manufacturing a transmission belt according to claim 3, wherein a pair of core wires of S twist and Z twist cord surrounded by adhesive rubber is wound around a resin mold.   The method for manufacturing a transmission belt according to claim 6, wherein the cross section of the core wire surrounding the adhesive rubber is rectangular or flat.   The method for manufacturing a transmission belt according to claim 7, wherein an area occupied by the adhesive rubber is 20 to 150% in a cross section of the core wire surrounding the adhesive rubber. The method for producing a transmission belt according to any one of claims 3 to 8, wherein an ethylene-α-olefin elastomer is used for the main rubber as the rubber composition.

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